Note: Descriptions are shown in the official language in which they were submitted.
~7~75 K . KIMMIC E~ - 2/3
(Re~llsion)
Ba_k(~r-_n~ of the Invention
The present lnvention relates to a methocl and apparatus for color
marking insulated electrical conductors. The metllod and arrangement ~ -
for marking insulated electrical conductors lncludes a stream of color ¦ -
material continuously emerglng under pressure from a spray nozzle
disposed at a right angle to the electrical conductor and is caused to
oscillate by a deflection system sl~b)ected to a high alternating voltage,
The deflection voltage for the stream of color material ensures that
the color rlng marks are produced at all marking frequencies coming -
lnto question.
Such arrangements for color marking lnsulated electrical conductors
are known and have proved good in practlce. In the known marking
apparatus, the deflection system is subjected to a sinusoidal alternatlng ;
voltage. This results ln a sinusoidal deflectlon of the stream of color
lS material, which produces, ln a lcnown manner, a half ring on the
longltuclinally advancinç~ extruded lnsulated electrical conductor at the
zero crossing of the sinusoldal oscillation. The production of two
,
ring marks composed of two separately produced half rings functions
excellently for a wide range of rlng spacings and extrud~ take-off speeds,
Difficulties may be encountered only with very large ring spaclngs,
which correspond to low frequencies of the deflection voltage, and/or
. . .
at high extruder take-off speeds for the following reason.
- To be able to produce the whole spectrum of ring marks at the
high extruder take-off speeds of modern extruders insulatlng the electrical
- 25 conductor, streams of color material are needed which are deElected at
frequencies between about 20G and 2,000 Hz (hertz). At a constant
pres~ure of the color material, the number of wave ~ains of the deflected
color stream between the point of orlgln, l,e. the deflecting elecirodes,
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1~P7~75 K KIMMICH - 2/3
(Revi slon)
and the marking plane varles by a factor of l0 also.
When the number of wave trains of the s1nusoidally deflected
stream of color material is small, l.e., at a low deflectlon frequency
or with a large ring spacing anà/or at a hlgh extruder take-off speed,
the conductor, whlle the stream of color materlal is pass1ng over 1t,
travels a distance v~hich is not negllgible. As a result, the ring mark
becc~mes wider, lncreasingly oblique, and dlstorted in the form of two
half circles. In addltion in the known marking apparatus, the ampll-
tudes of the stream osclllations are not generally equal to each otherD
One of the reasons for this is, for example, that the spray nozzles
have dlfferent dlameters when a small amount of color material has
deposited in one oE the nozzles. ~nother reason may be that the color
material in the feed pipe to one spray nozzle is given a charge dlfferent
from that applied ln the other feed pipe, and this may result 1n different
lS deflection properties.
Summary of the Inven_ion
An object of the present Invention 1s to provide a method and
arrangement for ~enerating a deflection voltage for the s~eam of color ~i
material which ~nethod and arrangement prevents the above-explained
phenomenon, i.e . ~ the inclination of the half ring at low deflection
~requencles of the stream of color material.
Another ob~ect of the present inventlon is to provide means whereby
the amplitudes of both streams of color material can be simultaneously
ad~usted to the same magnitude in a simple manner, thereby eliminaeing
the need for complicated individual control of the two stream amplitudes.
A feature of the present invention is the provision that at least
at low marklIlg i~3quencies, the deflectlon systern is sublected to a
~7~75
deflection voltage consisting of rectangles having semicircular top portions
thereon.
Another feature of the present invention is the provision that the
color material has a conductivity between 0.5 and 2 micromhos per centimeter
and that the spray nozzles are intercolmected via a potentiometer whose
slider or wiper is connected to a voltage source having one terminal grounded
and providing a high DC (direct current) voltage, and that the valves insert- -
ed in the pipes coupling the color material to the spray nozzles are grounded.
According to a broad aspect of the present invention, there is
provided a method for color marking a moving insulated electrical conductor
by a stream of color material continuously emerging under pressure from a
pair of spray nozzles disposed in a given spaced relation with respect to :~
each other along said conductor and on opposite sides of said conductor,
each of said strea~s of color material being caused to oscillate by a deflec-
tion system subjected to a deflection voltage, comprising: at least a step
of generating said deflection voltage including generating a waveform con-
sisting of rectangles each having a semicircular top portion.
According to another broad aspect of the present invention, there
is provided in an arrangement for color marking a moving insulated electrical
conductor by a stream of color material continuously emerging under pressure
from a pair of spray nozzles disposed in a given spaced relation with respect :-
to each other along said conductor and on opposite sides of said conductor,
each of said streams of color material being caused to oscillate by a ::
deflection system subjected to a deflection voltage, at least a first
arrangement to generate said deflection voltage comprising: a first elec- .
tronic stage to convert a sinusoidal control voltage to an output voltage
consisting of rectangles each having a semicircular top portion; a second
electronic stage coupled to said first stage to provide said output voltage
at the output of said second stage; a third electronic stage coupled to said
first stage to provide an inverted version of said output voltage at the
output of said third stage, a push-pull amplifier circuit coupled to said
second and third stages to amplify said output voltage at the output of said ::
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second stage and to amplify said inverted version of said output voltage
at the output of said third stage; and a high-voltage transformer coupled
to said amplifier circuit to step up the voltage of the resultant output
voltage of said amplifier circuit to a high voltage and provide said
deflection voltage for coupling to said deflection system.
Above-mentioned and other features and objects of this invention ~
will become more apparent by reference to the following description taken ~-
in conjunction with the accompanying drawing, in which:
Fig. 1 shows schematically the apparatus for color marking
insulated electrical conductors in accordance with the principles of the
present invention;
Fig. 2 shows a basic circuit arrangement for generating the
deflection voltage in accordance with the principles of the present invention;
Fig. 3a shows part of a conductor with a color ring mark produced
with a sinusoidal deflection voltage of low frequency of the prior art, and
Fig. 3b shows part of a conductor with a ring mark produced with
a low-frequency deflection voltage consisting of rectangles having semi-
circular top portions thereon.
Fig. 1 shows the extruded insulated electrical conductor 1 which
is to be provided wi-h colored ring marks a* intervals a with conductor 1
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K. KIMMICH - 2/3
113 7~6 7S (l~evision)
advancllag in tl~ d~rectic-n of the a~row. The ring mark is formed suc-
cessively from two half rings each of which ls produced by one of the
two spray nozzles 2. These spray nozzles 2 are disposed on opposlte t
sides of conductor 1 and spaced from each other a given axial distance
S such that the amplitude of the second stream of color material is æero
when the first half ring passes by the second of spray nozzles 2. The
deflection of the streams of colored materlal is effected by the deflectlng-
electrode systems 3, which are sub~ected to hlgh alternating voltages
derived from the deflection voltages Ul and U2, respectlvely, by
transformation in high-voltage transformers 4.
From a str)rage tank (not shown), the color material ls transferred,
by means of a gear pump 5 driven by a motor M, through a buffer vessel
6 (dashpot) into the pipe 7, from which it can move to spray nozzles
2 after valves 8 have been opened. The color material not hitting con-
ductor 1 is collected in conventlonal catch devices (not shown) and
returned to the storage tank.
The block diagram of Fig~ 2 shows the basic circult arrangement
for generating a deflection voltage which is suited to sinusoidally
deflect the s~eam of color material, emerging from spray nozzles 2
at a constant speed, within a wide frequency range in such a way that
colored rings are produced on conductor 1. This circuit arrangement
includes an operational amplifier 9 employlng nonlinear-feedback via
a variable resistor and two back-to-back diodes in parallel. The output
oi the operational amplifier 9 is connected to two further operational
amplifiers 10 and 11. Operatlonal amplifier 10 provides an inverted
output signal, and operational amplifier 11 provides a non-inverted
output signal. A followin~ push-pull power amplifier stage, lndlcated
13V7~36~7S (Revision)
by transistors 12 and 13, produces from the output slgnals of the !`
Gperational amplifiers 10 and 11 hlgh-power slgnals which are trans-
formed to a high volta~e in the high-voltage transformer ~ and mada
avallahle at the deflecting-elec~ode systems 3 as the deflection
voltage.
The actual waveEonn of the deflection voltage, an alternating
voltage cGnsisting of rectangles having semicircular top portions
thereon as shown in Fig. 2, is generated by the nonlinear-feedback
operational amplifler 9. Operational amplifier 9 operates as follows.
Applied to the input of the operational amplifier is a sinusoidal con-
trol voltage whose peak amplitude is considerably larger than the
forward voltages of the diodes in the feedback path (example: dlode
forward volta~e 0.5V, amplitude of the sinusoidal control voltage
6-lOV). The feedback then has the following effect. At amplitude
values of the control voltage whlch are smaller than the diode forward
voltage, the dlodes do not contribute to the feedbaclc, l.e., the galn
of the operatlonal ampliiier 9 ls determined only by the variable resistor
.
and can be chosen to be suitably hlgll. At amplitude values of the
~; control voltage which are larger than the diode forward voltage, the
feedback ls increasingly determined by the diodes, whose r~sLstance
decreases with increaslng signal amplitude, i.e., the gain decreases.
In the present case, this means that that portlon of the sinusoidal
control voltage which lies below the diode forward voltage is ampliiled
very strongly, while the portlon lying above the diode forward voltage
is ampli~led less stron~ly and even weakensd. Thus, operational
amplifier 9 provldes an alternating voltage whose shape resembles a
rectangle having a semlcircular top portion thereon, and whose amplitude
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~ K. KIMMICH - 2/3
~LO /~ 75 (Revision) ~
is nearly inclependent of the value of the input voltage after exceeding
the diode forward voltage~
As mentioned by ~Nay of introduction, deflection voltages of dif-
ferent frequency are needed for the production of colored rings spaced
different dlstances apart, and at different ex~uder talce-off speeds
of the conductc)r. If the sinusoidal control voltage at the input of
op~rational ampliEler 9 hasl at all frequencles coming into question,
an amplltude which ls considerably larger than the diode forward
voltage, the deflection voltage, too, will have the aforementioned wave-
form at all fre~uencies.
Howeverl since this waveform ls needed only in the case of
de~lection voltages with low frequency, as also mentioned by way of
introduction, it ls advantageous to derive the sinusoidal control
voltage in a low~pass ilter from an existing square-wave voltage,
This has the advantage that at low frequencies - as desired - a
deflectiorl voltage is generated whose shape resembles a rectangle
having a semicircular top portion thereon, and which turns into a
deflection voltage approximating a sinusoldal waveform as the frequency
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increases . `
~0 Thls is due to the fact that, because of the characteristic of the
low~pass filter, the amplitude of the sinusoidal control voltage decreaæs
with increasing frequency. The distortion of the waveform of the
`~ ~ sinusoidal c~ntrol voltage in the nonlinear-feedback operational
amplifier 9 de~creases with decreasing amplihlde of the sinusoidal
control volta~e. When the amplltude is smaller tha~l the dibde forward
voltage, there is no distortion because the feedback componont is
rendered inef~sctive by the dlodes. The output signal of the operational
amplifier is then a purely sinusoldal osclllation,
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1078~75 K KIMMIC}I - 2/3
~ !
Fig. 3a shows what happens lf with large ring spaclngs and/or
at a high extruder take-off speed, the colored rings are produced by
means of a sinusoidal deflection voltage of low frequency as in tha
prior art arrangement mentloned above. During the time lnterval in !~
which the s~ream of color material, oscillating at a low frequency,
passes through the range of the zero amplitude and, consequently,
over conductor 1, the latter travels the dlstance b. Thus, the half
ring 14 applied to conductor t is oblique.
If, however, a waveforrn as shown in Fig. 2 is used at low-
frequency deflection voltages, the stream of color material, deflected
at a low frequency, will pass through the zero-amplitude range much
faster as a result of the greater slope steepness. The half ring 1~ is
no longer inclined, as can be seen ln F'ig. 3b.
Fig, 1 shows the arrangement for adjusting equal amplitudes of
color s~reams. It consists of a high-resistance potentiometer R each
of whose terminals is connected to one of spray nozzles 2, while lts
wiper is connected to a variable high-voltage DC generator 9 whlch
provides a DS:: voltage between O and 6 kV (kllovoltsl for example.
The other electrode of the high-voltage generator and the valves 8 are
2 0 grounded .
Since the color material, in order to be deflectable at all, should
have a given conductivity, the color material between the grounded
valves 8 and the spray nozzles 2 offers high resistances Rl and R2
across which a voltage appears in the circuit of Fig. 1. By moving
the wiper of potentiometer R, different voltages can be applied to the
spray nozzles 2 whereby the two streams of color material are glven
different charges, which norrnally results in di~erent stream arnplitudes,
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~ ~7~j;75 K, KIMMICH - 2/3
(Revl sion)
If the stream amplitudes are already dlfferent from each other, they
can be made equal to one another by adjustlng the wiper. As may be
seen, this ls done ln a simple manner and wlthout the need to control
the voltages at the spray nozzles 2 indivLdually.
While I have described above the princlples of my inventlon in
connection with specific apparatus it ls to be clearly understood that .
this description is made only by way of example and not as a llmitation
to the scope of my lnventlon as set forth ln the objects thereof and in .
the accompanying clalms.
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